The invention relates to a fastening device for manipulation proof fastening of a first component on a second component, wherein the fastening device has a screw which has an actuating region arranged in a receptacle of the first component and a threaded region which adjoins the actuating region and can be brought in retaining engagement with the second component. The invention also relates to a component arrangement.
In many connections of components, for example the first component and the second component, it is desirable to prevent a manipulation of the connection or at least make the manipulation of the connection apparent. The term manipulation hereby refers in particular to undoing the fastening. For example the first component and the second component are part of a housing, which encloses a device, in particular an electrical device, at least partially, preferably completely. The housing insofar prevents for example that a person can come into contact with the device from outside the housing. This is in particular the case when the device is configured as electrical device and contains high-voltage components which during their operation are impinged with high voltages, in particular of at least 100 V, at least 200 V, at least 300 V, at least 400 V or at least 500 V. The first component and the second component can hereby together form the housing, wherein for example the first component is present in the form of a covering device and the second component as a housing shell, which can be closed by the covering device.
The first component is fastened on the second component at least partially with the aid of the fastening device, wherein the fastening device has the screw. The screw has at least the actuating region and the threaded region. The former serves for engagement with a fastening tool, for example a key (wrench, screwdriver) or the like on the screw. For this purpose the actuating region has preferably an appropriate outer contour and/or a recess with an inner contour that is adapted to the fastening tool. The inner contour can be any desired screw head drive for example a slot, an internal square, internal hexagon, a cross slot, a hexagon socket, a Torx-contour and/or an internal serration. Of course also manipulation-proof variants of these screw head drives can be realized so that the inner contour is present as inner hexagon-TR, Torx-TR, Tree-wing, Torq-Set or Pentalobe. The actuating region is for example configured as a screw head. In another embodiment the screw head only forms a part of the actuating region.
Directly or indirectly adjoining the actuating region in axial direction relative to a longitudinal center axis of the screw is the threaded region. The threaded region has a thread, preferably an outer thread. When fastening the first component to the second component the thread engages in the second component. For example the thread hereby interacts with an inner thread formed in the second component. As an alternative the thread can of course also be configured as self-cutting thread or the like. Between the threaded region and the actuating region a connecting region can be provided, which in particular does not have a thread. After fastening of the two components to each other the actuating region is to be at least partially, in particular completely, arranged in the receptacle of the first component. In this way access to the actuating region is at least made more difficult because a user can no longer bring a tool in operative connection with the actuating region for releasing the fastening.
The state of the art includes for example the patent document FR 2 239 146. Also so-called breakaway bolts are known. In such breakaway bolts the screw head tears off during fastening, in particular when a defined torque that acts on the screw head is applied or exceeded. The breakaway bolt can then only be loosened with a special tool or by special measures such as drilling. This means however that during the fastening of the components to each other the screw head accrues as waste and that the loosening of the connection is very complicated.